Elevator.



D. L. LINDQUIST & F. HYIVIANS.

ELEVATOR.

APPLICATION FILED DEC, 1. 1915. t 1 ,283,827. Patented Nov. 5, 1918,

3 SHEETS-SHEET 1.

i0 N a m i w 6% g Q A TTOR/VE Y UNITED STATES PATENT OFFICE.

DAVID L. LINDQUIST, OF YONKERS, NEW YORK, AND FREDERICK HYMANS, OF GLENA RIDGE, NEW JERSEY, ASSIGNORS TO OTIS ELEVATOR COMPANY, OF JERSEY CITY,

NEW JERSEY, A CORPORATION OF -NEW JERSEY.

ELEVATOR.

I Specification of Letters Patent.

HEISSUED Patented Nov. 5-, 1918.

To all whom it may concern:

Be it known that we, DAVID L. Lrxnonrs'r, a subject of the King ofSweden, residing in Yonkers, in the county of Westchester and State ofNew York, and FREDERICK HYMANS, a citizen of the Netherlands, residingin Glen Ridge, in the county of Essex and State of New Jersey, haveinvented a new and useful Improvement in Elevators, of which thefollowing is a specification.

Our invention relates in general to load carrying devices, and isdirected more particularly to an electrically controlled elevator orhoist.

An object of the invention is the provision of automatic means foreffecting an exact landing of a load carrying device such as an elevatorcar, at a predetermined point or points regardless of the load and speedof the device. I

Other objects of the invention will appear hereinafter, the novelcombinations of elements being pointed out in the appended claims.

In the drawings accompanying this spec1- Iication, Figure 1 representsin elevation view one embodiment of our invention; Fig. 2 is an end viewof Fig. 1; Fig. 3 is a sectional view of the combined friction brake andcoupling shown in Figs. 1 and 2; Fig. 4 is an end view of Fig. 3 shownin part section; Fig. 5 is a wiring diagram of a system of directcurrent electrical circuits which may be used in carrying out ourinvention.

Like reference characters denote similar parts in all of the figures.

Generally speaking, our invention comprises an elevator or other loadcarrying device adjapted to be operated at different speeds by means ofdiiferent motors, and means for automatically transferring the load fromone motor to another motor as the load carrying device approaches itsstopping point.

It has long been recognized that one of the means for effecting anaccurate stop of an elevator car at a landing or other stopp ng pointconsists in reducing the speed before reaching the same.

When a single speed reduction where a high degree of accu racy instopping is required, and this is true particularly when the elevatorcar is operated by an electric motor at high speed under a widevariation in load. By reason of our invention we are enabled to reducethe speed of the car to any desired predetermined low speed just beforemaking a landing so as to insure an accurate or exact landing regardlessof the load and also resulting in other advantages which will be pointedout later on. While the invention lends itself to any hoistingapparatus, it is particularly adapted to an automatically controlledelevator. v

Referring to the drawings, the particular embodiment of our inventiontherein illustrated comprises a cable sheave or winding drum A which inthe present instance is operatively connected through the worm gearing Bto an electric motor C although the motor and sheave A could be directlyconnected if so desired. The gearing B is also connected through acombined clutch and brake D and worm gearing E to an additional electricmotor F having a brake G associated therewith. .The motors C and F maybe of any desired kind of power units such for example as alternating ordirect current electric motors, the latter type of motor being shown byway of illustration with a View to simplicity.

The combined brake and clutch D which operates to slow down the hoistingdrum and permit a transfer of the load from the main motor C to theauxiliary motor F, is shown in detail in Figs. 3 and 4;, and'comprises apair of brake shoes 1, 1, adapted frictionally to engage a brake pulley2 secured on the shaft 3 of the motor 0. Each brake shoe is carried by acorresponding lever 4 pivoted at 5 to the frame 6, the other end of eachlever 4 being acted upon by compression spring 7 tending to force theshoes into frictional braking engagement withthe pulley 2. In order torelease the brake shoes from thepulley 2, we provide a pair of bellcrank levers 8, 8, pivoted at 9 to the frame 6, the vertical arm of eachlever terminating in a rounded nose 10 in horizontal alinement with asliding, rod 11, while the horizontal arm of each iever 8 engages thecorresponding lever 4-, .2, through an adjustable screw 12, 12.

The franc 6 is journaled in the gear casing 13 and carries a worm wheel14 meshing with a worm 15 secured to the shaft 16 of the auxiliary motorF shown in Fig. 2.. An electromagnet 18 is'arranged to operate thelevers 8, 8, to effect the release o'f the brake shoes 1, 1, and thesame comprises. a fixed and movable magnet core 17 and 19, respectively,the latter'being connected to one arm of a bell crank lever 20, whilethe other arm of this lever carries an adjustable screw 21 ooacting Withthe sliding rod 11.

The operation of the apparatus is as follows When. all parts are atrest, the magnet 18 of the combined brake and clutch D is deenergizedand the brake shoes 1, 1, are ap plied thus coupling the winding drum Aup to the auxiliary motor F which is prevented from accidental rotationby reason of the brake G which is applied at this time. The first stepin the operation is to excite the magnet 18 torelease the brake shoes 1,1, and to. close a. circuit to the main motor C. This results insevering all connection between the hoisting-drum and the auxiliarymotor F, and allows the motor C to start the load, and after a shortperiod of acceleration, operate the latter at full normal running speed.Shortly before reachingthe desired floor landing or other stoppingpoint, the circuit to the motor C and magnet 18 is interrupted and thelatter allows the spring 7 to apply the brake shoes to the pulley 2.

The friction of the shoes on the pulley tends to drive the auxiliarymotor through the gearing E, but the motor F will not rotate at thistime, since it is prevented from doing so by the brake G. The effecttherefore of the brake clutch D is that of an ordinary friction brakewhich would eventually bring the hoisting apparatus to rest. When thespeed of the latter has been reduced to a suflicient extent, the brake Gand motor F are energized and the latter drives the load at a very lowspeed since the motor Facts on the load through a double gear reductioncomprising the worm gearing E and B. This slow speed is a constantspeedregardless of the load and is maintained until the load substantiallyreaches whereupon the circuit to motor F is interrupted and the brake Gapplied to stop and hold the load exactly at the landing.

It will be observed that when the load carrying device is being driven.at slow speed by the auxiliary motor F, the maximum torque which can beexerted upon the hoisting drum is limited'to the friction existingbetween the brake shoes 1, 1, and the pulley 2. This feature is of greatpractical value particularlyin the case of inclined railways orammunition hoists having a ositive or head-on landing stop. Under theusual practice, failure to stop at the proper instant is almost certainto damage the hoisting machinery or other parts,

the landing within limits which will not permit excessive strains on thehoisting apparatus or other parts in case of overrun.

Referring to Fig. 5, we show a system of direct current circuits whichmay be used where the main and auxiliary motors C and F, respectively,are direct current shunt wound electric motors. In this figure Hrepresents an elevator car or other-load carrying device adaptedautomatically to be operated by push buttons arranged in the car and ateach floor landing. R and R designate the switches for starting,stopping and reversing the main motor C while K is a starting resistanceautomatically controlled by the accelerating magnet J. The parts 1', 1-,K and J in like manner control the starting, stopping, reversing andaccelerat ing, respectively, of'the auxiliary motor F. I represents afloor controller which is operated by some -moving part of the hoistingapparatus such as the winding drum in the usual way, and the same,acting in conjunction with the relay L, eli'ects the transfer ofthe loadfrom the main to the auxiliary motor at the proper time in accordancewith the position of the car with respect to a designated floor'landingorother stopping point. if desired the floor cont-roller may comprise aseries of switches in the hatclr way operated by the car orcounterweighteither arrangement of floor controller being well known inthe art. As indicated on the drawing, the system of push buttons isarranged for three fioor landings and the car is at rest at the secondfloor. The operation is as follows: A person on the ground floordesiring to use the elevator, presses the button 22 at that floor. Thisestablishes a circuit from the main. through the door contacts 23,throughthe reversely wound magnet coils of the magnet 24, contacts 25,push button 22, winding of the floor relay 26, to the contact 27 of thefloor controller I. The circuit continues through the segment 28 andcontact 29 to the winding of the reversing switch R and is completed byway .of the conductor 30 to the main. The reversing switch R and floorrelay 26 both operate to close their respective contacts, the switch Rclosing a circuit to the motor C through the starting resistance K, andsimultaneously opening any possible circuit to the auxiliary motorthrough the bottom contacts of the switch as long as the switch is inraised position. The operation of the relay 26 establishes a selfholding circuit comprising the left hand this circuit being in shunt tothe circuit including the contacts 25 and the push button 22. Inconsequence'of this self-holding circuit the contacts 25 becomeseparated and hence the other floor buttons are rendered dead and therecan be no interference in the operation in case another of the buttonsbe operated As the motor C starts to build up a counter-electro-motiveforce, the accelerating magnet automatically and graduallyshort-circuits the starting resistance J in a well known way and themotor quickly runs up to full normal speed. In the meantime the relay Lhaving its operating magnet connected in a direct shunt to the mainmotor armature separates its contacts 32.

It will be observed that the closing of the reversing switch It?completes a circuit to the magnet 18 of the brake clutch D at thecontact 34, hence the brake shoes 1, 1, are released from frictionalengagement with the pulley 2 and the auxiliary motor F is entirelydisconnected from the hoisting apparatus.

The main motor continues to operate the hoisting apparatus at full speedwhile the floor controller is slowly being revolved in a clockwisedirection until finally as the car approaches the ground floor, thecontact 27 of the floor controller bridges the segment 28 and contact35. A circuit in parallel to the magnet of the reversing switch R is nowclosed, said circuit comprising the contact 35, segment 36, contact 37and the Winding of the reversing switch 1". The latter at once closesits contacts to establish the proper connections for the auxiliary motorF and brake G but neither of them as yet receives current from the mainline since their circuit is still open at the contacts 32 of the relay Land also at the bottom contactsof the reversing switch. As the floorcontroller continues to revolve the contact 27 runs off-of the segment28 and hence the circuit to the reversing switch R is interrupted andthe switch drops its contacts thereby opening the circuit of the mainmotor C arrdthe circuit to the winding 18 of the brake clutch D. Thelatter now acts as a brake on. the hoisting apparatus and the speed ofthe car is gradually reduced. As

- the speed of the motor 'C falls off, its counterelectuomotive forcebecomes less and less until finally the relay L is unable longer tomaintain its core in raised position and the contacts 32 are connectedtogether The circuit to the auxiliary motor F and brake G is nowcompleted at these contacts and the motor F automatically takes up theload and operates it at greatly reduced speed. Just as the load reachesthe landing, or an instant before as the case may be, the floorcontroller rotates the'contact .35 out of en gagenient with the contact27, and the circuit, including the floor relay 26 and-reversing switch1" is interrupted at this point. The switch?" immediately opens thecircuit of the auxiliary motor F and eifects the applicationof the brakeG to stop the hoist exactly at the floorlanding. 1

If one or the other landing push buttons be operated, the car willautomatically respond and come to rest at the corresponding floorlanding just as in the case of the button 22 just described, the floorcontroller I automatically controlling both of the motors in everyinstance in both directions of car travel.

The operation from one of the push buttons in the car is in effect thesame as that produced by a' floor button although the operating circuitis somewhat different. For example, upon pressing the button 22 in thecar, a circuit is closed from the main through the door contacts 23,left hand winding of the magnet 24, wire 38, winding of magnet 39,through the push button 22', floor relay 26, contacts 37 and 29 of thefloor controller, and through the reversing switch magnet It to themain. The magnet 24: immediately separates the contacts 25 to preventany interference from the floor buttons, while the magnet 39 closes itscontact 5 to establish a self holding circuit for both of the magnets 24and 39 including the door contacts 23 and resistance 40. This selfholding circuit is maintained after the floor controller has efiectedthe stop of the car at the designated floor landing and is not brokenuntil the landing door has first been opened, thereby opening one of thedoor contacts 23, and the door then closed. This safety feature preventsany operation from a floor button unless and until'the operator in thecar has first restored the system to initial position by opening andthen closing a door.

In reviewing the operation, it will be observed that the load istransferred from the main motor to the auxiliary motor only after thespeed of the car has been very materially reduced, and in every case theamountof speed reduction is predetermined and controlled by the relay L.The latter may readily be designed or adj usted'in any of the well knownways, such for example as by means of a set screw 4:1, to short circuitits contacts at any predetermined speed reduction of the motor so as toobtain the best results in practice. While the relay L supplies a simplemeans for determining when the auxiliary motor will take hold of theyload, it is obvious that any other device responsive to speed condition,such for example as a centrifugal governor, would effect a similarresult.

It is desirable that the speed of the car or load carrying device shallfirst be reduced to a speed substantially the same as the normal speedof the auxiliary motor before the circuit to the latter is closed andits brake G released in order that the auxiliary motor may take up theload without any shock or'jar. In some cases it may be desired to effecta full stop of theload carrying device before a landing is reached andbefore the auxiliary motor is brought into operation. This may readilybe done by merely adjusting the relay Lor other speed responsive deviceso that it will not establish the auxiliary motor circuit until the mainmotor has either completely or substantially come to rest.

In order that the load carrying device shall invariably stop level witha floor or exactly at a given point in its travel, it is essential thatthe speed be substantially reduced before the stopping point is reachedand that-the load from then on shall be op erated at a constant lowspeed regardless of the load. This necessitates a constant speedauxiliary motor regardless of what type it may be. In the particularembodiment of our inventionthis motor is represented as a shunt wound'direct current electric motor operating directly across the line, andit is well known that it is the inherent characteristic of such a motorto run at a fixed speed even though the load varies within wide limitsand particularly so when the resistance of the motor armature is made aslow as possible. If an alternating current induction motor is used inplaceof a direct current motor, the system of electric circuits would ofcourse have to be modified somewhat so as to be adapted to that type ofmotor, but "the alternating current motor will operate at constant speedeven though the load varies, since such motor is inherently a constantspeed motor. Other motors, such as steam, hydraulic,-etc., could also beused providing they be suitably governed as is customary so as tooperate at constant speed with varying loads.

In'any event, it is intended that the auxiliary motor be arranged tooperate the load at a comparatively low speed, whereas the main motormay operate the load at any speed desired.

From the foregoing, it is obvious that the apparatus disclosed iscapable of being modified in many ways without departing from the spiritand scope of our invention, and therefore We desire not to be limited tothe precise construction and arrangement of parts herein set forth.

What we claim is 1. In an elevator, the combination of a car, main andauxiliary hoisting motors therefor, a circuit -fdr the main motorincluding a switch, controlled automatically by movement of the car toopen the said circuit, a circuit for the auxiliary motor includingcontacts controlled automatically by mined point in its travel and uponits speed for transferring the load from one motor to the other;

4:. In an elevator, the combination of a car, a motor connectedtherewith, automatic means for retarding said motor as the carapproaches a predetermined stopping point, and an additional motoradapted to be connected to. drivethe car at a constant slow speed afterthe speed of the latter has been reduced a predetermined amount.

5. In an elevator, the combination of a car, a motor connected to drivethe car, means for retarding the speed of said motor as the carapproaches a predetermined sto ping point, a second motor adapted to eoperatively connected to the ear upon the operation of saidmotor-retarding means, and means dependent on the speed of the car forautomatically controlling said second motor.

6. In an elevator, the combination of a car, a motor connected todrivethe car, means for retarding the speed of said motor as the carapproaches a predetermined stopping point, a second motor adapted to beoperatively connected to the car upon the operation of saidmotor-retarding means, and means dependent on the speed of the car forautomatically starting said second motor.

7. In an elevator, the combination of two electric hoisting motors, andmeans for closing the line circuit to one of said motors in accordancewith the counter-electro-motive force of the other motor.

8. .In an electric elevator, the combination of two hoisting motors,means for disconnecting one of said motors from the car upon startingthe car, and means for again connectingthe said motor and car after thespeed of the other motor has been reduced a predetermined amount.

' 9. In an electric elevator, the combination of two hoisting motors,electro-responsive means for disconnecting one of said motors from thecar upon starting the car and for again connecting the said motor andcar after the speed of the other motor has been reduced a predeterminedamount.

10. In an elevator, tho-combination of an electric hoisting motoradapted to drive the car at normal full speed, an additional elec tricmotor adapted to drive the car at a reduced speed, an electricallycontrolled friction clutch between said additional motor and the car,electro-responsive means for simultaneously releasing said clutch andclosing a circuit to the motor for full speed operation of the car,automatic means, for applying said clutch and interrupting the circuitof said last named motor as the car approaches a predetermined stoppingpoint, means dependent for its operation upon a predetermined speedreduction of the car for closing a circuit to the additional motor 7 iif? whereby the latter operates to drive the car at reduced speed, abrake for the additional motor, and means for interrupting the circuitof said additional motor and applying the brake to stop the car at thepredetermined stopping point.

in testimony whereof, We have signed our names to this specification inthe presence of two subscribing Witnesses.

DAVID L. LINDQUIST. FREDERICK HYMANS. Witnesses:

GEORGE Imnrspr, Cmaancn Enem.

